The ABC of Embryo Selection

Embryo selection is a decisive phase in a fertility treatment. The success of the treatment will depend on it to a great extent.

In the last ten years, assisted reproduction techniques have made great progress. Thanks to this fact, each phase of the process has been improved: from the obtaining of samples to the embryo transfer and subsequent implantation of the embryo that will give birth to a healthy baby.

Our team of embryologists is in charge of selecting the best embryo. They monitor the embryonic development daily. The embryos selected for transfer will be those with the highest probability of reach an implantation.

Criteria for selecting the best embryo

In order to select the best embryo, embryologists make decisions based on a series of criteria: the number and appearance of the cells that make up the embryo (morphological), its rate of cell division (kinetic) and its chromosome composition (genetic).

Thanks to the evolution of technology, the tools that embryologists have to make a correct embryo selection have improved, allowing better rates of implantation and births.

The selection according to morphology and kinetics has been improved by the appearance of time-lapse technology, present in our clinic’s laboratory.

Time-lapse incubators

Time-lapse monitoring of the embryonic development allows to see the evolution of the embryo without altering the incubation conditions; and not like in traditional monitoring which consisted of observing the embryos under the microscope periodically, altering the continuity of their culture.

The combination of the monitoring in time-lapse incubators and the evaluation by the embryology team, helps to determine which embryos are most likely to implant and produce a pregnancy.

Being able to select the embryos for transfer according to objective criteria has improved the success of the treatments, improving both the rate of implantation and the rate of births.

Role of genetics in Embryo Selection

In order to select the embryos following the general criteria, at IVF-Spain we use advanced techniques with preimplantation genetic testing, now known as PGT-A (Preimplantation Genetic Testing for Aneuploidy).

At IVF-Spain we have our own programme for the genetic diagnosis of embryos whose aim is to precisely detect possible alterations in the 23 pairs of chromosomes that make up each cell of the embryo.

This test is important because it increases notably the rate of births by the selection of the embryos without chromosomal alterations.

An aneuploid embryo (with chromosomal alterations) can be implanted correctly, but it can lead to spontaneous miscarriage. By performing embryo selection through PGT-A, we manage to increase the rate of a successful implantation. And even more important is that reducing the rate of genetically caused miscarriages we automatically increase the rate of healthy births.

This test is performed by an embryo biopsy in which some cells are extracted from the developing embryo (around day 5 of its growth). Genetic material is obtained from the inside of these cells in order to analyse their chromosomal status.

Around day 5 the cells of the embryo have separated to form two differentiated cell masses. One of them is the embryoblast (the inner cell mass) that will become the future baby, and the other is the trophectoderm that will turn into the placenta. In our clinic we perform the biopsy of the trophectoderm and with this we manage to minimize the risk to the embryo, since these are cells that will be quickly replaced.

In most European clinics the extraction of cells for later analysis is normally done on day 3 of the embryonic development, which can negatively affect the viability of the embryo, since its cell count is still very low, and most importantly, they are not yet differentiated providing less reliable diagnoses.

The importance of the best Embryo Selection

At IVF-Spain we have the most advanced technology that allows us to maintain our high pregnancy rates by transferring a single embryo: the best.

Both the medical team and the team of embryologists recommend avoiding multiple transfers, since a double pregnancy can lead to various complications, both for the mother and the baby, such as premature birth or delayed intrauterine growth.

Through the development of strategies adapted to the patient and the use of the most advanced techniques, such as our state-of-the-art embryo selection process, we have managed to distinguish ourselves and specialize in the most complex cases.

Always pursuing a single objective, to achieve pregnancy with the least number of attempts avoiding adding more wear and tear to the future parents.